Parsing for semidirectional

We study the computational complexity of the parsing problem of a variant of Lambek Categorial Grammar that we call semidirectional. In semidirectional Lambek calculus SD[ there is an additional nondirectional abstraction rule allowing the formula abstracted over to appear anywhere in the premise sequent's left-hand side, thus permitting non-peripheral extraction. SD[ grammars are able to generate each context-free language and more than that. We show that the parsing problem for semidireetional Lambek Grammar is NP-complete by a reduction of the 3Partition problem. ...

6p bunmoc_1 20-04-2013 40 2   Download